20 Questions with Detailed Rationales
Clinical Judgment
Question 1
Clinical Scenario
A 74-year-old male with a history of stage 3 chronic kidney
disease (CKD) and chronic heart failure is admitted to the
medical-surgical unit for a respiratory infection. The provider
prescribes an aminoglycoside antibiotic, which is known to be
eliminated primarily through glomerular filtration. The client's
current serum creatinine is $1.9 \text{ mg/dL}$ (elevated), and
his estimated glomerular filtration rate (eGFR) is significantly
reduced.
Question Stem
Based on the client's renal status and the pharmacokinetic
profile of the medication, which physiologic alteration must the
nurse anticipate?
A. Increased rate of drug metabolism in the liver
,B. Prolonged half-life and increased risk of toxic systemic
accumulation
C. Rapid clearance of the drug requiring a higher dosage
frequency
D. Decreased protein binding leading to subtherapeutic blood
levels
Correct Answer
Correct Answer: B. Prolonged half-life and increased risk of toxic
systemic accumulation
Detailed Rationale
This question requires clinical judgment regarding the
pharmacokinetic process of excretion. When a drug is primarily
eliminated via the kidneys, impaired renal function directly
slows down its clearance from the body. A reduced eGFR and
elevated serum creatinine mean the kidneys cannot filter the
medication efficiently, which prolongs the drug's half-life (the
time required for the plasma concentration of a drug to
decrease by 50%). If the dose or frequency is not reduced, the
drug will accumulate in the bloodstream, leading to systemic
toxicity. Aminoglycosides are high-alert, nephrotoxic, and
ototoxic drugs, making renal monitoring paramount.
Option A is incorrect because renal impairment does not
inherently accelerate hepatic metabolism. Option C is incorrect
,because clearance will be delayed, not rapid; a higher
frequency would worsen toxicity. Option D is incorrect because
while protein binding can alter active drug availability, renal
failure primarily delays elimination of this drug category, and
accumulation leads to toxic, not subtherapeutic, levels.
Learning Objectives
After completing this question, the learner should be able to:
• Explain the impact of impaired renal function on a drug's
half-life and systemic clearance.
• Predict the risk of drug toxicity based on laboratory
findings of renal impairment (creatinine and eGFR).
• Identify necessary dosage modifications for medications
primarily excreted by the kidneys in older adults.
Medication Safety Focus
Monitoring / Renal Impairment
Question 2
Clinical Scenario
A nurse on a pediatric unit is preparing to administer an oral
liquid anticonvulsant medication to a 4-year-old child who
weighs $16 \text{ kg}$. The medication label reads: "125 mg/5
mL." The provider's prescription is for "80 mg PO twice daily."
Question Stem
, Which action by the nurse is essential to ensure safe medication
administration?
A. Use a standard household teaspoon to measure the required
volume of $3.2 \text{ mL}$.
B. Round the dose to $125 \text{ mg}$ ($5 \text{ mL}$) to
match the stock concentration volume easily.
C. Utilize an oral dosing syringe to measure exactly $3.2 \text{
mL}$ and verify the calculation with a second nurse.
D. Dilute the medication in a $240 \text{ mL}$ (8 oz) bottle of
apple juice to mask the flavor.
Correct Answer
Correct Answer: C. Utilize an oral dosing syringe to measure
exactly $3.2 \text{ mL}$ and verify the calculation with a second
nurse.
Detailed Rationale
Pediatric medication administration demands extreme precision
due to narrow therapeutic indexes and weight-based dosing
variations. The formula $\frac{\text{Desired}}{\text{Have}}
\times \text{Quantity}$ results in:
$$\frac{80 \text{ mg}}{125 \text{ mg}} \times 5 \text{ mL} = 3.2
\text{ mL}$$